1. Field of the Invention
The present invention relates to a circuit arrangement for time-division multiplex telecommunication exchange systems, particularly pulse code modulation (PCM) telephone exchange systems, comprising time-division multiplex (TDM) lines on which a respective plurality of time channels form a time-division multiplex, and on which different, successively following time slots are assigned to the time channels, and on which the time slots are arranged in pulse frames, and on which the same respective time slot is assigned to each of the individual time channels in the various following pulse frames. More particularly, such a circuit arrangement comprises time-slot multiples which are equipped with information memories and holding memories, by way of which time-slot multiples the time channels on a time-division multiplex line connected at the input can be individually switched to time channels on a time-division multiplex line connected to the output, and comprises a respective signal channel provided per time-division multiplex and serving as one of its time channels for the transmission of individual switching identifiers assigned to the remaining time channels, the time slots of the signal channel being combined over a plurality of pulse frames, just as the pulse frames, into successively-following super pulse frames, within which time slots within the super pulse frames which serve as connection-associated message channels are assigned to the remaining time channels, and further comprising information memories in which the right mode is cyclically sequenced in accordance with the successive time slots of the channels of the incoming multiplex lines and which has a read mode which is sequenced in accordance with the memory element addresses of the information memories stored in the holding memory, the information memory element addresses being cyclically read in accordance with the successive time slots of the channels of the time-division multiplex lines connected at the output.
2. Description of the Prior Art
In time-division multiplex telecommunication systems as described, for example, in the periodical "telcom report" (Vol. 4/1981/supplement), a respective common signal channel is provided for a plurality of time channels, for example, for 30 time channels. The signal channel serves for the transmission of signaling information in individual assignment for each of the remaining 30 time channels which can be considered as message channels individually and randomly selectable for the completion of individual connections. The sub-information transmitted across a time-division multiplex line and individually corresponding to the time channels are arranged in pulse frames in a universally-known manner. A pulse frame always encompasses a series of sub-information of which a respective sub-information is assigned to a respective time channel. One of the sub-information is assigned to the signal channel. Since the sub-information assigned to the signal channel within a single pulse frame would not suffice in order to signalize the individual switching identifiers individually assigned to the message channels for the remaining time channels serving as message channels in the appertaining time-division multiplex line, the sub-information corresponding to the signal channel are combined over a plurality of pulse frames into super pulse frames within which the chronological position, i.e. the chronological relationship to the respective beginning of each super pulse frame, individually specifies the assignment of a sub-information to one of the remaining time channels employed as message channels. For this purpose, the sub-information is assigned to the signal channel within a respective pulse frame can be assigned to a respective or to two or more of the remaining time channels of the appertaining time-division multiplex line which are employed as message channels, or the sub-information within two or more successive pulse frames can be assigned to one each of the remaining time channels. Usually, the sub-information within a single pulse frame and assigned to the signal channel is sub-divided into two parts with the same respective plurality of bits, of which each part is individually assigned to a respective remaining time channel, i.e. the time channels serving as message channels.
It is standard in time-division multiplex telephone exchange systems (v.,for example, see the periodical "telcom report"), to accept the signaling sub-information serving for the signaling of switching identifiers and assigned to the time channels of each of the time-division multiplex lines with the assistance of a decentralized control device of a terminating group (LTG) (the same also applies to analog trunk lines and to analog subscriber lines) and to forward the same to a central control unit. The central control unit processes the signaling sub-information and designationally conducts the same to the decentralized control devices of those terminating groups by way of which the connections were forwarded which proceed over the time channels belonging to the time-division multiplex line.
In order, however, to significantly reduce the considerable control unit load which occurs from the mere switching identifier forwarding by signaling sub-information which are always taken by the term groups from the time channel of each of the time-division multiplex lines serving for the signaling of switching identifiers and to subsequently resupply the time channels according to the exchange data of each individual connection of all through-connected connections, and arrangement has been created according to the German Letters patent No. 1,910,974, corresponding to British patent specification No. 1,263,006, which are fully incorporated herein by this reference, which, for the switching of sub-information serving for the signaling of switching identifiers, from a switching matrix for the through-connection of message connections ("connection switching matrix") additionally provides a further switching matrix ("signal switching matrix") for the through-connection of such connections, by way of which further switching matrix the sub-information corresponding to the message connection and serving for the signaling of switching identifiers can be switched. This circuit arrangement proceeds from the fact that each of the sub-information is provided with a respective assignment information which specifies the assignment to the respective message time channel.